If this is true and the collection of processes has 0 members, this means that no processes with this name were found, so there's no point in trying to terminate them. Like all variables in VBscript it has a default value, and this is “Raise”. Did the page load quickly? But before that, what the heck is up with the second statement? a fantastic read

Error Handling In Vbscript Tutorial

The second one never calls Blah at all if an error is raised, because it resumes to the next statement. It is divided into 3 sections: Throwing and Catching Errors. Top of page Interpreting Ping Status Codes In several listings so far, we tried to bind to WMI on a remote machine and used the success or failure of this operation

Return code 0 - Terminated If no processes are found that match the target process names, the output looks like this: Copy C:\scripts>eh-sub-terminateprocess-returncode.vbs No processes named calc.exe found. The VBScript Err object is a unique kind of object that you don't have to create or get: it is instantiated automatically by VBScript when the script runs. The subtlety in the "resume next" mode is best illustrated with an example. On Error Resume Next Vbscript W3schools The Movie Top of page Show: Inherited Protected Print Export (0) Print Export (0) Share IN THIS ARTICLE Is this page helpful?

Who Should Read This Book? Vbscript Error Handling Best Practices The Movie. (Who knew errors could inspire great cinema?) With the Raise method, VBScript offers a little-known capability: you can use this method to create a VBScript error in one part Seems like it gets the last error which is a big difference. –Damien Golding Jun 13 '14 at 0:47 Despite MS's documentation suggesting that err.clear needs to be used http://stackoverflow.com/questions/157747/vbscript-using-error-handling In ASP 3.0, using the VBScript On Error Resume Next statement circumvents ASP’s built-in exception handling and replaces it with VBScript’s less flexible error handling system.The Err Object The Err object

You have to explicitly check whether the Err.Number property is non-zero after each operation. Vbscript Error Message Top of page Handling Errors in a Subroutine If a script checks for errors in more than one place, it may make the script easier to read and reduce script length You can use Err.Number > 0 to test if there is any runtime error has been raised or not. Instantiates classes that may not exist on a machine.

Vbscript Error Handling Best Practices

It's very important to use Clear after each time you check Err. http://ss64.com/vb/onerror.html Consider these three programs, for example. Error Handling In Vbscript Tutorial Method return codes also fall somewhere on that semantic frontier. Vbscript On Error Exit The WSH script in Example 4.8 illustrates the importance of resetting the Err object after an error occurs.Example 4-8. Failing to Reset the Err Object Dim x, y ,z On Error Resume Next

On Error Resume Next ' Note that 1/0 generates error 11 -- division by zero ' Note that a(2) generates error 9 -- subscript out of range a = Array (0,1) http://wppluginmarket.com/error-handling/vb-net-error-handling-msgbox.html TerminateProcess also returns the Terminate return value to the calling statement. The WMI SDK lists return code values and meanings for most methods of WMI classes. Reply Alex French says: December 11, 2007 at 3:38 am This is probably the best explanation I've seen so far. Vbscript Error Line Number

If Foo.Bar raises an error, then the first one passes Empty to Blah. Vbscript Goto For example, these two do have the same semantics: On Error Resume Next If Blah Then Wscript.Echo "Hello" End If Wscript.Echo "goodbye" On Error Resume Next If Blah Then Wscript.Echo "Hello" Once the error handling flag is turned on, execution will not be stopped when a runtime error occurs.

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It runs to completion, so (a) = 11, (b) = 9 (c) = 11, (d) = 9, (e) = 9, , (g) = 9, (h) = 9, (i) = 11, (j) Before we plunge into the details, here's a public-service announcement: error-handling is not free. You can get into similar trouble with other constructs. If Err.number <> 0 Then This is done by inserting a statement like the following at the start of a procedure:On Error Resume NextThis tells the VBScript engine that, should an error occur, you want it

Do they have the same semantics? So it's possible to turn error-handling on with On Error Resume Next just before you want to check the Err object, and turn it off after with On Error GoTo 0. Listing 4 adds to the previous examples by trying to retrieve the state of a service specified by strService. navigate here When the first runtime error occurred on statement, x = 1/0, execution continued because the error handling flag was turned on.

Blah2 is not in 'resume next' mode, so it aborts itself, records that there was an error situation, and returns to its caller. The second statement turns off 'resume next' mode if it is on. If Err <> 0 Then Select Case Err.Number Case DIVIDE_BY_ZERO If Len(txtDenominator.Value) = 0 Then strErrorResultText = "Missing!" Else strErrorResultText = "'" & txtDenominator.Value & "'" End If strErrorMessage = "Error: In Listing 1, make sure that strComputer is the name of a non-existent or inaccessible computer so the script will produce an error.

So if you want to handle errors then you need to include an On Error Resume Next in each procedure where you want to use If Err.Number… because the default is Then" and "Select Case" Loop Statements - "For", "While", and "Do" "Function" and "Sub" Procedures Built-in Functions Inspecting Variables Received in Procedures ►Error Handling Flag and the "Err" Object Error Handling If the value of Err.Number is 0, no error has occurred. We have seen what happens when the error handling flag is turned off in the previous section.

On Error Resume Next DoStep1 If Err.Number <> 0 Then WScript.Echo "Error in DoStep1: " & Err.Description Err.Clear End If DoStep2 If Err.Number <> 0 Then WScript.Echo "Error in DoStop2:" & more hot questions question feed lang-vb about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation You can put your unsafe part of code eg into a function, which will interrupted immediately if error occurs, and call this function from sub containing precedent OERN statement. We can do this because the default property of the Err object is Number, so VBScript allows us to use Err by itself as shorthand for Err.Number.

Doctor Scripto spends most of his time in a parallel reality, but sometimes even his virtual world collides with the cantankerous reality of Windows bits, x86 silicon and Ethernet cables (if You can not catch those errors, because it depends on your business requirement what type of logic you want to put in your program. They simply verify whether the object reference was successfully created. I will discuss how the Err object can be interpreted later, but now I focus on some scoping issues.

Number (dec) : -2147217350 Number (hex) : &H8004103A Description : Invalid object path Source : SWbemServicesEx The source of both errors is SWbemServicesEx. In this case there's no comparison: IsObject is true if objPrinter refers to a valid object, and false if not. The TerminateProcess function calls the Terminate method of Win32_Process on the object reference passed to it. The VBScript engine generally catches these the first time we try to test the script.

Putting On Error Resume Next at the beginning of the script, as we often do, makes it apply to the entire body of the script.